1. Field of the Invention
This invention relates to an ultrasonic Doppler apparatus capable of measuring the flow-rate by utilizing the ultrasonic Doppler effect.
2. Description of the Related Art
It is expected that a color Doppler flow imaging system can be used to quantize the regurgitation flow in a noninvasive manner instead of the conventional X-ray cardiography. At present, however, no method for grading the severity of the regurgitation flow by use of the color Doppler method is presented. A method which has been presented is to effect the grading based not on the absolute flow-rate of the regurgitation flow jet but on the geometric characteristics such as the length, width and area of the regurgitation flow jet. The jet flowrate is obtained by flow velocity.times.cross-sectional area. However, it is extremely difficult to correctly measure the cross-sectional areas of the orifice of the regurgitation flow, such as valvular regurgitation flow, shunt flow and stenosed flow, by means of the Doppler method.